The present invention relates to a filter element for separation of a liquid, in particular an element for removing oil from air, having a drainage tube through which the separated liquid can be removed. In addition, the present invention relates to a drainage system comprising the drainage tube and to a filter device comprising a filter element according to the invention.
Filter elements for separating a liquid from a fluid stream are generally known in the art. They are used, for example, for removing oil from compressed air in compressed air systems which are supplied with air by an oil-lubricated compressor. Another possible application is for removing entrained oil from crankcase gases from an internal combustion engine. In filter elements through which fluid flows continuously from the inside to the outside, the separated liquid collects in the interior of the filter cartridge, which preferably has a cylindrical design, and is removed from there with suction via a drainage tube extending into the interior of the filter cartridge. This drainage tube may be an integral component of the upper end disk of the filter element, thus making it possible to secure it in the position required for suction removal. However, a filter element with a fixedly installed drainage tube is complicated to manufacture, which is why such filter elements are not very economical.